The study evaluated emission rates for five different vehicle
types and discovered that particulate matter produced through
electricity generation was actually worse than emissions from
conventional vehicles.

For electric vehicles, combustion emissions occur where
electricity is generated rather than where the vehicle is used.
In China, 85 percent of electricity production is from fossil
fuels, about 90 percent of that is from coal. The authors
discovered that the power generated in China to operate
electric vehicles emit fine particles at a much higher rate than
gasoline vehicles.